In recent years, a trail has been made on fusing different communication systems, and making best use of these communication systems while allowing them to express their features.
One example (referred to as “known example”, hereinafter) can be found in a system configuration making a mobile terminal device operable, by fusing a wireless LAN (Local Area Network) represented by IEEE (Institute of Electrical and Electronics) 802.11 and a third generation mobile phone system (3G system, 3G: 3rd Generation).
In particular, FMC (Fixed Mobile Convergence) attracts public attention as a challenge of fusing mobile phone and stationary phone.
Patent Document 1 discloses a wireless communication device connectable to wireless bearers provided by a plurality of wireless communication systems.
The wireless communication device is such as allowing a wireless bearer switching unit to select and switch a wireless bearer of an appropriate wireless communication system, based on wireless bearer type information acquired by a wireless bearer information acquisition unit, that is, information indicating which of communication charge, data transmission speed and data capacity of the wireless bearer should be given with priority, and wireless bearer priority reference information stored in a memory unit, that is, communication charge, data transmission speed and data capacity of the wireless bearer.
Patent Document 2 discloses a terminal device capable of switching, among a plurality of communication systems, from a wireless communication system currently in use to other switchable communication system.
The terminal device is such that a throughput-adapted first value of the communication system currently in use derived by a first throughput derivation unit, and a throughput-adapted second value of the communication system to be switched derived by a second throughput derivation unit to a threshold value determining unit, a threshold value with respect to quality of transmission path is determined by the threshold value determining unit based on the first value and the second value, and the communication system currently in use is switched to a destination communication system based on the threshold value determined by the threshold value determining unit and the value of quality of transmission path derived by a transmission path quality derivation system.    [Patent Document 1] Japanese Laid-Open Patent Publication No. 2004-080707    [Patent Document 2] Japanese Laid-Open Patent Publication No. 2004-357213